The Swedish evolutionary geneticist Svante Pääbo was recently awarded the 2022 Nobel Prize for physiology and medicine in recognition of his ground-breaking research on aspects of human evolution, particularly for his work on the Neanderthal and Denisovan genomes. A well-deserved honor indeed.
Pääbo’s research built on a long history of previous research – as is of course usually the case in science – but it is interesting to note just how long ago people were already attempting to figure out the shape and branches of the human family tree, as well as how and when who got to be where.
In 1786 Sir William Jones, a British civil servant in India, noticed a strong relationship between Sanskrit and ancient Greek. This, naturally, was not by accident.
Eventually investigations showed the existence of an immense family of Indo-European languages, among others the Germanic, Celtic, near Eastern and north Indian languages. Just how this situation came to be remained uncertain for a long time.
The Italian population geneticist Luigi Luca Cavalli-Sforza was one of the most famous figures in the study of human migrations, for which purpose he studied the distribution and inheritance of blood groups across living populations.
He also collaborated with linguists because, like human beings, languages migrate and change over time. His best-known book on this subject is undoubtedly Genes, People and Languages, published in 2000.
Modern techniques have, to a large extent, cast his work into little-read footnotes, aspects of the discarded history of the subject.
During the period of research which formed the basis of his aforementioned book, the status of molecular biology was relatively primitive in comparison to what is known and possible today.
Genomic analysis then was slow, cumbersome and extremely expensive, hence the use of contemporary living populations, which unfortunately have interbred so much that the results are mostly meaningless – it makes more sense to use genetic material extracted from long-dead bones, obtained from periods when populations were “pure.”
Of course, it also helps that modern genomic analyses are quick and literally a million times more cheap than when Cavalli-Sforza worked.
David Reich was trained by one of Cavalli-Sforza’s students and as such is an experienced molecular biologist.
His book is a fascinating and reasonably extensive review of human migrations as reflected by the changes in human DNA – including that of Neanderthals and Denisovans – over the last 50,000 to 60,000 years.
This includes the colonization of the Americas as well as the migrations and blending of population structures in Europe, India and East Asia.
Such blending of mixing of populations is in fact one of the outstanding characteristics of human history.
An interesting (and, for me, new) finding is the existence of so-called ghost populations, populations with no extant living members but whose existence can be deduced from their remnants in our DNA.
It is Reich’s ideal to bring about a so-called “American-style genomics factory” where historical DNA can be researched. However, given the historical contexts of at least some of the population which can be studied, I can see several obstacles in his way – previously exploited groups will no doubt voice objections.
Some of these objections will not be without merit, but that is a subject for another discussion.
Chapter 11 (The Genomics of Race and Inequality) is undoubtedly the most controversial part of Reich’s book.
Wokeness and self-styled Social Justice Warriors are exerting significant pressure on the natural sciences, so much so that research undertaken by Reich and others to chart the prevalence of disease among various ethnic groups have become unacceptable because it is supposedly racist.
In fact, the mere presence of this chapter in Reich’s book gave one reviewer cause for alarm because it could in some mysterious way promote racism. (Don’t ask me, I don’t know either.)
Reich writes: “The concern is so acute that the political scientist Jacqueline Stevens has even suggested that research and even emails discussing biological differences across populations should be banned, and that the United sates ‘should issue a regulation prohibiting its staff or grantees… from publishing in any form – including internal documents and citations to other studies - claims about genetics associated with variables of race, ethnicity, nationality, or any other category of population that is observed or imagined as heritable unless statistically significant disparities between groups exist and description of these will yield clear benefits for public health, as deemed by a standing committee to which these claims must be submitted and authorized.’ ”
Given the nature of the censorship advocated for by Stevens it is hard to see how any such research will ever get off the ground.
Reich discusses the various concepts of ethnicity briefly and knowledgeably. I found this statement very insightful: “I have deep sympathy for the concern that genetic discoveries about differences among populations may be misused to justify racism.
"But it is precisely because of this sympathy that I am worried that people who deny the possibility of substantial biological differences among populations across a range of traits are digging themselves into an indefensible position, one that will not survive the onslaught of science.”
“The findings that the nature of human population structure is not what we assumed should serve as a warning to those who think they know that the true nature of human population differences will correspond to racial stereotypes.
"Just as we had an inaccurate picture of early human origins before the ancient DNA revolution unleashed an avalanche of surprises, so we should distrust the instincts that we have about biological differences.
"We do not yet have sufficient sample sizes to carry out compelling studies of most cognitive and behavioral traits, but the technology is now available…”
I found this book extremely interesting, but it is not a work which can be read in one afternoon. It describes a complex subject which is being investigated by means of complex technology and a certain amount of background knowledge, while by no means essential, will definitely be useful.
The link below leads to an interesting video in which Reich tells the audience about the latest findings.
